Toward the end of a daylong conference that touched on everything from video games to water meters in a sprawling exploration of how data should—but often doesn’t—influence urban policy, UChicago economist Jens Ludwig homed in on a central point. “In the area of public policy, we are not so far advanced from the era of applying leeches,” he argued. “This is a big problem.”

Ludwig, who directs the University of Chicago Crime Lab and codirects its Urban Education Lab, had been arguing that policy proposals should go through the same evidence-based scrutiny and randomized trials that new drugs and medical devices must pass before the Food and Drug Administration allows them on the market. But right now, he said, “that is not at all how public policy gets made in the United States, or in any other country for that matter. We basically just make it up. We look around; we take a guess about how the world works; we have some intuition. We have a hunch.”

For the past 19 years, as part of a Housing and Urban Development–funded study, Ludwig has been testing out one of those hunches: the idea that neighborhood environment is a major contributing factor to children’s performance in school. An “extensive theoretical literature in social science” has grown up around this conviction, he said. But when it was tested in a randomized controlled experiment that relocated low-income families in five American cities to neighborhoods with less poverty, the theory didn’t hold up. Contrary to his own expectations, the effect on children’s test scores, Ludwig said, was “basically zero.” Of course there are plenty of moral reasons to support housing policies that reduce economic segregation, he added, “but if you think that those polices are going to be a panacea for disparities in how kids are doing in school, you will be mistaken.”

Ludwig’s comments echoed those of other speakers, including UChicago vice president for global engagement Ian Solomon, who gave the conference’s opening remarks. “Conceptually we know that policy should be data and evidence driven,” Solomon said. But too often other things get in the way: tight budgets, inadequate manpower, poor communication, the crisis of the moment. “Fads are as influential as facts,” he added.

Called “The Informed City: Data-Driven Approaches to a More Just, Equitable, and Sustainable City,” the conference was held at the Gleacher Center in early March. It offered a prelude to the World Urban Forum, a biennial United Nations colloquium that took place in April in Medellín, Colombia.

More than a dozen panelists—academics, city officials, and activists—discussed how data is already being put to use in cities, how it will be, and how it should be. Water reclamation officials talked about emerging technologies (so far mostly in Europe) and the need for more in an industry that hasn’t changed much since the 19th century: ways to more efficiently clean and reuse water, sensors to help improve water quality in green buildings, crowdsourcing mechanisms so that citizens can alert officials when water is being wasted, desalination technologies in freshwater deserts.

Sharon Feng, executive director of the University’s Institute for Molecular Engineering, discussed the nascent research partnership between UChicago and Israel’s Ben-Gurion University of the Negev to find nanotech solutions to the growing problem of getting clean, accessible, plentiful water. David St. Pierre, executive director of the Metropolitan Water Reclamation District of Greater Chicago, declared, “The future industry in this country needs to be environmental.”

Other panelists discussed the city of Chicago’s open-data portal and digital tools in the works to synthesize the millions of individual pieces of data collected daily on traffic, weather, 911 calls, and myriad others; such synthesizing tools together with predictive algorithms will help officials anticipate everything from public emergencies to rat infestations. Sharing the panel with Ludwig, Northwestern University economist Jonathan ­Guryan, one of four codirectors of the University of Chicago Urban Education Lab, described how data helped demonstrate that cognitive behavioral therapy reduces recidivism among juvenile violent offenders, a fact that wasn’t unequivocally clear without the numbers. “Sometimes social problems persist because they’re ­really hard to solve, and sometimes they persist because we’re focused on the wrong thing,” Guryan said.

A similar sentiment underlay the remarks by UChicago gynecologist Stacy Tessler Lindau, AM’02, director of the University’s South Side Health and Vitality Studies. She described a data-collection program that works to improve South Side residents’ lives by connecting them to neighborhood resources that could help them live healthier lives: grocery stores, pharmacies, community centers. “In our cities, our physicians are good at diagnosing disease and writing prescriptions for medicine,” Lindau said, but for the vast majority of patients, that’s not enough to get well and stay well.

What they need, she said, is “everything else”: exercise, fresh fruits and vegetables, social support, mental health support. These things can be harder to find in low-income neighborhoods, like many of those served by the University’s clinics and physicians. “And it’s a moral distress,” Lindau said, for a doctor “to say to a patient: ‘You have diabetes and here’s your prescription for insulin, and then goodbye.’”

Lindau’s solution is a program called MAPSCorps, which began five years ago and hires local high schoolers to map and inventory every community organization and business on every block of the South Side. “The youth know that the data they collect are connecting grandma to the resources she needs,” Lindau said. “They’re not just doing a menial task; they’re generating data people can use and that are going to make their communities more vital.” So far, she said, they’ve covered 75 square miles of the South Side: 24 communities, 10,000 “assets.” Every place serving the public is a potential asset “until proven otherwise,” Lindau said. “So liquor stores are an asset. Maybe you can get a banana there. Maybe you can have a nice conversation.”

Later John Tolva, former chief technology officer for the City of Chicago, summed up a key element of the day’s discussion. “Cities have always been information driven,” he said. “It’s one of the reasons people move to cities.” He recalled digging up Chicago’s streets and finding that “below the water pipes and the sewer mains were telegraph lines.” That means, he said, only half-joking, that communication and the exchange of information were even more fundamental than hygiene to the people who built the city. “Opportunities come from a dense communication and information network.” Today, the pace and volume have changed, but not the need for the information.